SN55109A, SN55110A, SN75109A, SN75110A, and SN75112 are dual line drivers with improved output current regulation and stability over supply voltage and temperature ranges, constant-current outputs, high speed, standard supply voltages, high output impedance, high common-mode output voltage range, TTL-input compatibility, inhibitor available for driver selection, glitch-free during power up/power down. SN75112 and external circuit meet or exceed the requirements of CCITT Recommendation V.35.